1. Field of the Invention
This invention relates generally to devices and other apparatus facilitating sealed access with surgical instruments across a body wall and into a body cavity.
2. Discussion of the Prior Art
In several areas of surgery there exists a need to have mechanisms or devices that can seal a body cavity or space, and yet permit the introduction of surgical instruments of different sizes such as guidewires, endoscopes and staplers. Typical of these areas of surgery is laparoscopic surgery which relies on surgical instruments inserted through the abdominal wall to reach an operative site within the abdominal cavity. In order to increase space around the operative site within the cavity, insufflation gases are typically introduced to inflate the cavity and elevate the abdominal wall. This pressurizing of the abdominal cavity is referred to as pneumoperitoneum. In this context, the need to seal the body cavity or space arises from the need to maintain the pneumoperitoneum even when the instruments are present.
Trocars have been commonly used to provide instrument access in laparoscopic surgeries. These trocars have included elaborate seal structures having zero seals which prevent escape of the gases in the absence of instruments, and instrument seals which prevent escape of the gases in the presence of instruments. Unfortunately, the instrument seals have been able to accommodate only a narrow range of instrument diameters. Where wider ranges were desired multiple seal pairs had to be provided.
Some instruments such as surgical staplers and those having diameters up to about 37 mm have been too large for trocar access. Furthermore, present trocar seals typically require two valves, one for forming an instrument seal in the presence of the instrument, and the other for forming a zero seal in the absence of the instrument. Accordingly, there is a need in the art for a surgical access device that can function both as a zero seal and as an instrument seal, and that can accommodate a wide range of instruments having diameters up to about 37 mm.